In recent years, hybrid vehicles are becoming more widespread. Electric vehicles have also been developed rapidly. The hybrid vehicles and the electric vehicles are mounted with a high-voltage battery, an inverter and a motor. The inverter converts direct-current (DC) power supplied from the high-voltage battery into alternating-current (AC) power which is then supplied to the motor. Specifically, the AC power is supplied to the motor via high-voltage cables. In the hybrid vehicles and the electric vehicles, since the high-voltage cables are used for an electrical connection between the inverter and the motor as described above, there is required means for preventing radiation noise from the high-voltage cables.
Patent Literature 1 discloses a conventional technology for preventing the radiation noise which is explained below with reference to the drawing.
Referring to FIG. 5, there is shown an inverter 1. The inverter 1 is covered with a conductive shield cover 2. The shield cover 2 is connected to a vehicle body 4 via a grounding wire 3 and grounded. FIG. 5 also shows a motor 5. The motor 5 is covered with a conductive shield cover 6. The shield cover 6 is connected to the vehicle body 4 via a grounding wire 7 and grounded. The inverter 1 and the motor 5 are electrically connected to each other via three shield wires 8. The shield wire 8 includes a core wire 9, an insulation member 10 and a braid 11. Each end of the braid 11 is connected to the shield cover 2, 6 via a grounding wire 12 and grounded.
In the above-described structure, the inverter 1 is supplied with DC power from a DC power source. The inverter 1, with this supplied power, produces three-phase AC power by operating a semiconductor switch located inside the inverter 1. The core wires 9 of the shield wires 8 transmit the change in voltage created by the switching operation of the semiconductor switch.
Since the shield wires 8 connected to the inverter 1 and to the motor 5 are provided with the braids 11, it is possible to prevent the radiation of electro-magnetic wave from the core wires 9 to outside by connecting the braids 11 to ground at the shield covers 2 and 6.